It was previously shown that topical application of heparin produces enhanced bleeding from small vesseis and capillaries. Adenosine triphosphate at low concentrations is able to disalodge heparin bound to a receptor, counteracting its antihemostatic activity. This results led us to measure the amounts of heparin remaining in the blood after protamine neutralization of the patients subjected to cardiopulmonary bypass operation and to test the topical application of the nucleotide denosine triphosphate at a concentration of 10-4 mol/L significantly reduces the blood volume (p<0,005) oozed from the thoracic cavity of the patients (mean 288 ± 188 ml) when compared with controls (mean 564 ± 288 ml). Adenosine triphosphate at 5 X 10-5 mol/L reduces the blood loss to a mean of 370 ± 155 ml in the patients tested (p<0.08). About 10% of heparin of low molecular weight (< 6.0 Kda), which is also found in the oozed blood, is not neutralized by protamine. We suggest that the excessive blood loss of the patients is probably produced by low molecular weight heparins in the commercial preparations that are not neutralized by protamine.
bleeding in heart surgery